The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent that it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An internal combustion engine generally includes multiple cylinders that operate sequentially in four strokes: intake stroke, compression stroke, combustion stroke and exhaust stroke. When the engine stops, one of the cylinders may be in a compression stroke (i.e., where the gas charge is compressed). The compressed charge may push the cylinder down when the engine stops, causing the crankshaft to rotate in a reverse direction. If the reverse rotation of the crankshaft is not detected, the final rest position of the crank and cam shafts may be difficult to discern, thus making restarting of the engine more difficult.
Sensors may be used to monitor angular movement of the crankshaft but most often cannot determine whether a reverse rotation of the crankshaft has occurred. Upon restarting the engine, it may take an entire rotation of the crankshaft to determine the actual crankshaft angular position. As a result, the operation of the engine may be delayed when re-starting.